Asian Journal of Transfusion Science
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Year : 2014  |  Volume : 8  |  Issue : 1  |  Page : 62-63
Investigating weak A subgroups in a healthy lady: The blood bank limitations

Department of Transfusion Medicine, Apollo Gleneagles Hospitals, Kolkata, India

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Date of Web Publication7-Feb-2014

How to cite this article:
Das SS, Zaman R U, Safi M, Sen S, Sardar TP, Ghosh S. Investigating weak A subgroups in a healthy lady: The blood bank limitations. Asian J Transfus Sci 2014;8:62-3

How to cite this URL:
Das SS, Zaman R U, Safi M, Sen S, Sardar TP, Ghosh S. Investigating weak A subgroups in a healthy lady: The blood bank limitations. Asian J Transfus Sci [serial online] 2014 [cited 2022 Jan 19];8:62-3. Available from:


Weak A subgroups such as A 3 , A x , A end , A m , A y , and A el are often mistyped as group O and may be potentially dangerous with regards to whole blood transfusion. These subgroups can be serologically differentiated using recommended techniques. [1],[2] Special tests like serum glycosyltransferase estimation and genotyping are performed in advanced laboratories to confirm these blood groups. [3],[4]

We observed a discrepancy between the routine forward and reverse blood grouping of a 45-year old healthy lady. The forward group revealed 'O' positive and reverse showed 'A' group. No clerical errors and reagent problems were observed. We performed a detailed serological investigation on the lady's red cells with both tube technique and Gel method (DiaMed, Cressier s/Morat, Switzerland) [Table 1]. Since the red cells showed no agglutination with either Anti-A and Anti-AB, we suspected a possible A m or A y or A el phenotype. The red cells were then subjected to adsorption - elution tests using human polyclonal Anti-A as described elsewhere. [2] To our surprise the eluate reacted with the reagent 'A' cells indicating the presence of 'A' antigen on the test red cells. The result was then validated with a) the eluate showing agglutination with two different reagent 'A' cells at all phases b) eluate failing to agglutinate reagent 'O' cells and c) the final wash solution failing to agglutinate with all the four reagent red cells 'A', 'B', 'AB' and 'O' [2] [Table 2]. Blood groups of her husband and one son who were available then were confirmed to be 'O' positive. Saliva study showed that the lady was a secretor and carried both 'A' and 'H' substances thus excluding the probability of A el phenotype. Serologically 'Ay' is almost similar to 'Am' and even adsorption - elution test fails to differentiate the two phenotypes. In the present study Anti-A eluted from the lady's red cells reacted weakly with the corresponding reagent 'A' cells (Agglutination strength: 1+ by tube technique and 2+ by Gel) which is in favor of 'Ay' phenotype. In case of 'Am' phenotype such agglutination strength is significantly stronger. [1] Finally we reported the patient as "Weak A subgroup" Rh positive.
Table 1: Test on red cells and serum

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Table 2: Adsorption-elution test

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We advised both serum glycosyltransferase estimation and genotyping of the lady for confirmation of her weak 'A' subgroup. We were really in a dilemma as to how the reporting should be done in the present case. We were not sure whether designating the lady as "Weak A subgroup" Rh positive was a proper reporting format. Since confirmatory tests for weak 'A' phenotype is beyond the scope of most blood banks, there should be a system to report these weak 'A' individuals.

   References Top

1.Harmening DM, Firestone D. The ABO blood group system. In: Harmening DM, editor. Modern Blood Banking and Transfusion Practices. 3 rd ed. New Delhi, Jaypee Brothers Medical Publishers (P) Ltd.; 1998. p. 86-115.  Back to cited text no. 1
2.Bercher ME. Methods section 2: Red cell typing. AABB Technical Manual. 15 th ed. Bethesda: American Association of Blood Banks; 2005. p. 735-736.  Back to cited text no. 2
3.Heier HE, Namork E, Calkovská Z, Sandin R, Kornstad L. Expression of A antigens on erythrocytes of weak blood group A subgroups. Vox Sang 1994;66:231-6.  Back to cited text no. 3
4.Meng QB. Genetic analysis of an individual of Ay serologic phenotype. Nan Fang Yi Ke Da Xue Xue Bao 2009;29:1615-6.  Back to cited text no. 4

Correspondence Address:
Sudipta Sekhar Das
Department of Transfusion Medicine, Apollo Gleneagles Hospitals, Kolkata - 700 054
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Source of Support: None, Conflict of Interest: None

DOI: 10.4103/0973-6247.126699

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  [Table 1], [Table 2]

This article has been cited by
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[Pubmed] | [DOI]



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2006 - Asian Journal of Transfusion Science | Published by Wolters Kluwer - Medknow
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